Hearing devices come in many types and styles, large, small, thoroughly designed, visible, hidden, etc. A particular solution is typically chosen according to the need and wishes of a user. Some uses want an inconspicuous hearing instrument, which they do not need to handle/care about (mount demount, change/charge battery, clean, etc.).
EP2538701A2 describes a completely in the ear canal type hearing instrument, adapted for being located at least partially in the bony part of the ear canal. The hearing instrument is a self-contained instrument comprising microphone, battery, signal processing unit, and loudspeaker (and possibly other relevant functional parts for providing appropriate amplification (or attenuation) of an input sound and presenting it as a processed output sound to the residual volume of the ear canal close to the ear drum).
U.S. Pat. No. 8,630,434B2 describes a modular hearing device comprising an ear mould and an output module. The mould is arranged to have an opening with an inner surface, the dimensions and form of outer surface of the output module, the opening and the inner surface of the mould being adapted to allow the output module to be mounted in the opening, preferably tightly, at least over a part of their common spatial extension. At least one venting channel is arranged adjacent to the outer surface of the output module, so that sound waves can pass by the output module when inserted in a mould for insertion in a user's ear. The output module comprises functional components of the hearing device, at least including an output transducer.